Switching power supply for generating DC voltage by synchronous rectification

摘要

A switching power supply of a synchronous rectification type is provided. A transformer has at least a primary winding and a secondary winding. A main switching element switches input DC current via the primary winding. An auxiliary switching element is arranged on a side of the secondary winding for use in conducting commutation current. The auxiliary switching element is turned on after the main switching element is turned off. The main switching element is turned on immediately after release of exciting energy from the transformer is completed.